I have read several posts where people have experienced the same thing. I have tried some of their solutions but still having the problem.

Here is the history:
2 months ago, I was in Colorado and my atv started and ran great for 2 weeks and put about 200 miles on it.

About a month ago I started to notice it wasn't running as fast going down the road. It continued to get worse to the point that if I pressed the throttle all the way it would backfire.

I replace the carb with a new one. There is no mixture adjustments. no change.
Replaced the plug, coil and blug wire, nope, no change.
Then I read about the cam problem that these engines have, Pulled the cam, yep, the exhaust lobe pretty much gone. thought that would fix it. New cam and lifters adjusted to .006. nope, didn't fix it.

The engine starts easy, but starts bogging down at about half throttle. Now what? Any ideas?